The invention relates generally to a frequency-scan antenna array for the millimeter-wave region, and more particularly to an array of microstrip-type antennas which are switchable, for example, by means of electronically switchable ferrite Y-junction microstrip circulators.
A further aspect of the invention relates to an array of frequency-scan antennas in which each antenna has a ramped-microstrip construction.
Frequency-scan antennas are employed to provide inertialess electronic scan capability in the millimeter-wave region, particularly for radar systems. The inertialess scan feature is particularly important for surveillance, obstacle-avoidance and target-acquisition radars.
Antennas and antenna arrays of background interest are described in Stern et al., A MM-Wave Homogeneous Ferrite Phase Scan Antenna, Microwave Journal, Vol. 30, No. 4, pp. 101-108 (April 1987); Borowick et al., Inertialess Scan Antenna Techniques for Millimeter Waves, 9th DARPA/Tri-Service MMWave Conference Record (1981); and Collier, Microstrip Antenna Array for 12 GHz TV, Microwave Journal, Vol. 20, No. 9, pp. 67-71.
See also Stern et al., U.S. Pat. No 4,754,237 issued Jun. 28, 1988, titled Switchable Millimeter Wave Microstrip Circulator.
The contents of all noted prior art materials are incorporated by reference herein.